1. Field
One embodiment of the invention relates to an access control method and in particular to an access control method for controlling an access to content data through a network.
2. Description of the Related Art
As known, the digitization of household electrical appliances has moved forward in recent years.
For example, in Japan, flat-screen digital TVs such as a liquid crystal TV and a plasma TV having functions of receiving and playing back satellite BS digital broadcasting and terrestrial digital broadcasting, an HDD-DVD recorder for receiving an analog broadcast program and recording the program in an internal HDD in digital form, and the like are springing into wide use in households.
Many of the digital household electrical appliances have a network connection function. It is imagined that in the future, for example, a content display such as a digital TV will operate as a client and the user will be able to easily enjoy content without moving to the place where the content physically exists by accessing the content stored in an HDD-DVD recorder having a server function in another room through a home network.
However, generally such a home network often is connected to the Internet through a router and the client may find out an unauthorized server releasing copyrighted content to the Internet and may access the content stored in the server depending on the settings of the router, resulting in an infringement of the copyright.
In order to cope with the above circumstance, generally the server often adopts a method of conducting machine authentication and access control so as to protect against the fraud of releasing copyrighted content to the Internet.
For example, a method of using the MAC address of the client as identification information and managing the identification information by the server, thereby restricting access to content from a client outside the home is known. (For example, refer to JP-A-2004-343497 (publication number of the corresponding European patent application is EP1517480A1))
A method of determining whether the client is in or outside the home based on whether or not access to the same physical medium within a short time can be shared as the determination criterion is also known. (For example, refer to JP-A-2004-334756 (publication number of the corresponding European patent application is EP1536344A1))
However, in the related art described above, if an unauthorized server other than the server installing the related art described above exists on the Internet, there is a possibility that the client in the home may access the unauthorized server.
There is also a possibility that the server belonging to the home network installing the related art described above may have settings rewritten by unauthorized access from the outside so that the client in the home is induced to an unauthorized server on the Internet or is caused to make unauthorized access to a server on the Internet.